Dundee United moved back into contention for second spot in the Premiership with victory over fellow Europa League contenders Motherwell.

Slack defending handed United a commanding half-time lead through Ryan Dow and Gavin Gunning.

United went three clear when Gunning doubled his tally with a free-kick straight after the break.

Motherwell responded through a John Sutton penalty, but a United win never looked in danger.

Victory saw them narrow the gap to third-placed Motherwell to six points, although United have played one game more.

With Stuart McCall's men threatening to race 12 points clear of their hosts in the race for a Europa League spot, defeat was not an option for the Tangerines.

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As United rose to the occasion, Motherwell looked short of ideas and have conceded 11 goals in their last four games.

Sutton went close to opening the scoring early on when he met Keith Lasley's corner at the back post, but after that it was a dominant first half by the home side.

Andrew Robertson and Stuart Armstrong were denied by last-ditch defending after racing into the box, while John Rankin and Nadir Ciftci fired in efforts.

Motherwell's back-line were being asked plenty of questions, but the opening goal arrived all too easily for United when Dow pounced on Shaun Hutchison's poor back-pass and coolly slot the ball beyond the goalkeeper.

Sutton was still proving to be a danger whenever the visitors could bring him into the game and, when he stretched to nod the ball into the path of Iain Vigurs, the summer signing was denied by a fine Radoslaw Cierzniak save.

Back came United and Ciftci skilfully drifted past two black shirts and fired just over.

The intense pressure eventually paid dividends when Gunning fired United 2-0 ahead. Ciftci was peeled away from his marker to head low into the path of the United defender, who celebrated his return from injury with an easy finish.

Only a minute into the second half Gunning found himself on a hat-trick, driving in a free-kick that took a favourable deflection off James McFadden beyond Gunnar Nielsen.

Motherwell responded, though, as Sutton's short free-kick found Lionel Ainsworth in space and his low shot tested Cierzniak.

That was followed by a needless Ciftci handball, the Turk leaping in the air and punching McFadden's free-kick - and allowing Sutton to score from the spot.

The hosts lacked the same inventiveness after that, but Gunning and Ciftci wasted opportunities inside the area before Nielson was forced into a double save to thwart Gary Mackay-Steven and Armstrong.